The present invention relates to a laminate article of manufacture. More specifically, the present invention relates to a laminate comprising a silicone pressure sensitive adhesive and a fluorosilicone release liner.
The adhesive aggressiveness of silicone pressure-sensitive adhesives, hereinafter called SPSAs for brevity and convenience, is well documented in the silicone art. While aggressive adhesiveness, i.e. tack and/or adhesive strength, of SPSAs has utility it is also a significant problem. Whether the SPSA has the form of, for example, an adhesive layer on a substrate in the form of a roll of tape; an adhesive layer on an article protected with a peelable backing, such as a decorative trim item to be adhered to an automobile or a medical item to be adhered to the skin of a person; or a transfer adhesive layer protected on two surfaces by peelable backings, the SPSA must be separated from an adjacent surface before it can be used for its intended purpose.
Substantially every material that has been used as a protective backing or as a tape substrate for SPSAs has been given some sort of surface treatment to facilitate the removing of the adjacent surface from the adhesive without adhesive separation or transfer and with a force sufficiently small to avoid the tearing of the substrate, item or backing.
Recently, Brown and Stickles, U.S. Pat. No. 4,736,048, disclosed a fluorosilicone release liner which is said to be useful for releasing solvent-cast, heat-cured SPSAs with a force of no more than 200 grams per inch. Patentees provided examples of laminates comprising peroxide-cured SPSAs, which had been solvent-cast and heat-cured in contact with their fluorosilicone liner. However, they did not disclose any examples of a laminate comprising a platinum-cured SPSA.
In general, peroxide-cured compositions are used as silicone pressure sensitive adhesive compositions. For example see U.S. Pat. Nos. 2,736,721; 2,814,601; 2,857,356; 3,528,940; 3,929,704; 4,309,520; 4,584,355; 4,591,622; Canadian Patent No. 711,756; and British Patent No. 998,232. Platinum-cured SPSAs, also known as addition-cured SPSAs, are also known. For example, see U.S. Pat. Nos. 3,527,842; 3,983,298; 4,774,297; and Japanese Patent Application No. 283,343/86.
There is a trade-off between the release force needed to remove a SPSA from its liner and the adhesive properties of the SPSA subsequent to its removal from the liner. For example, a peroxide-curable SPSA can be formulated to have moderate to high levels of subsequent adhesion (&gt;1200 grams per inch) and subsequent tack (&gt;1100 grams per square centimeter); however these formulation have release which is unstable with aging. On the other hand, if the adhesive is formulated to have low release, low tack (&lt;800 grams per inch) are obtained.